This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application for APPARATUS FOR PAPER FEEDING AND CONTROL OF FEEDING POSITION FOR INK-JET PRINTER earlier filed in the Korean Industrial Property Office on Jul. 5, 2001, and there duly assigned Serial No. 39919/2001 by that Office.
1. Field of the Invention
The present invention relates to a printer, and more particularly, to a sheet delivery and position controlling apparatus for a printer which controls delivery and position of a printed sheet of paper discharged from the printer.
2. Description of the Related Art
In general, an ink jet printer is often required to successively print numerous sheets of paper. In this case, a first printed sheet is discharged into a sheet stacker through a discharging unit having a feeding roller and a discharging roller. Then, next printed sheet following the first printed sheet is successively discharged and dropped down on the top surface of the first printed sheet which has been already disposed on the sheet stacker.
Meanwhile, when the next printed sheet is discharged and placed on the top surface of the first printed sheet before a portion of ink material formed on the top surface of the first printed sheet is dried out, the next discharged printed sheet is stained or blurred with the ink material of the first printed sheet. In this case, a printing image formed by the ink material on the first printed sheet is damaged as well as the next printed sheet is stained with the ink material. Accordingly, printed images of both of the first and next printed sheets may be defective as a drawback. Therefore, it is disadvantageous that the printer is required an extended period of time for discharging the next printed sheet until the ink material of first printed sheet is dried out.
It is an object of the present invention to provide a sheet delivery and position controlling apparatus for an ink jet printer discharging a first printed sheet and a second printed sheet following the first printed sheet and extending a period of time for the second printed sheet to contact the first printed sheet once the second printed sheet is discharged.
It is another object to provide a sheet delivery and position controlling apparatus able to prevent the second printed sheet from being stained by wet ink material formed on the first printed sheet.
It is still another object to provide a delivery and position controlling apparatus able to prevent the first printed sheet from being damaged when the second printed sheet is discharged onto the first printed sheet.
It is yet another object to provide a delivery and position controlling apparatus able to maintain image quality formed on each printed sheet.
These and other objects may be achieved by providing a sheet delivery and position controlling apparatus for an inkjet printer including a sheet stacker, a dischargingunit having a sheet delivery roller for discharging in sequence printed sheets to the sheet stacker, and a delay unit having a swivel unit pivotally provided between the sheet delivery roller and the sheet stacker to move between a first position which does not interfere with the printed sheet discharged from the sheet delivery roller and a second position which interferes with the printed sheet discharged from the sheet delivery roller to delay the printed sheet placed on the sheet stacker by a predetermined period of time, a driving motor, a power transmission unit for transmitting power from the driving motor to the swivel unit to selectively swivel the swivel unit to the first position and the second position, and a control unit for controlling the operation of the driving motor.
The power transmission unit includes a driven gear coupled to the swivel center of the swivel unit to be swiveled together therewith, a worm gear provided to a shaft of the driving motor for being rotated perpendicular to a direction of rotation of the driven gear, and a clutch installed between the worm gear and the driven gear for transmitting power from the worm gear to the driven gear and controlling power transmitted to the driven gear to control the position of the swivel unit.
The clutch includes a worm wheel gear geared to the worm gear, a clutch shaft coupled to the center of rotation of the worm wheel gear for being rotated therewith, and being provided at one end with an inclined portion extended in diameter, a clutch gear provided to the clutch shaft for being cooperative to the driven gear and having a shaft hole inclined corresponding to the inclined portion, and a spring for elastically forcing the clutch gear toward the inclined portion to create a friction force between the inclined portion and the shaft hole.
The swivel unit includes a pair of swivel arms, a connecting members for connecting the pair of swivel arms, and guide members provided in the connecting member at an interval for guiding the sheet as contacting the underside thereof discharged by the sheet delivery roller at the second position.
The sheet delivery and position controlling apparatus of the present invention includes a stopper for limiting the moving range of the swivel arm displaced to the second position.